Method for removing chromium (VI) in water by stabilized nanoscale iron in air

A technology of nano-iron and hexavalent chromium, applied in the application field of nano-technology, can solve the problems of incapable of chromium-containing wastewater control, chromium pollution, unreasonable discharge, etc., and achieve the effects of good market prospects, convenient operation, easy use and transportation

Inactive Publication Date: 2009-10-21
NANKAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the inability to effectively control and unreasonably discharge the chromium-containing wastewater produced by these industries, there is often serious chromium pollution in surface water and groundwater in many areas.

Method used

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  • Method for removing chromium (VI) in water by stabilized nanoscale iron in air
  • Method for removing chromium (VI) in water by stabilized nanoscale iron in air
  • Method for removing chromium (VI) in water by stabilized nanoscale iron in air

Examples

Experimental program
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Effect test

Embodiment 1

[0018] Embodiment 1: In the Cr (VI) solution that initial concentration is 40mg / L, add the newly prepared nano-iron, place the nano-iron and common iron powder of two months in the air, make the concentration of nano-iron be 0.5g / L, the concentration of iron powder is 3g / L, such as figure 2 shown. Within 140 minutes, the removal rate of Cr(VI) of the two kinds of nano-iron can reach more than 95%, and the activity of nano-iron is not greatly affected after being stored in the air, and its removal effect on Cr(VI) Far better than ordinary iron powder.

Embodiment 2

[0019] Embodiment 2: To the Cr (VI) solution that initial concentration is 40mg / L, add the nano iron of new preparation, as image 3 As shown, when the nano-iron concentrations were 0.4, 0.5 and 0.6 g / L, the removal rates of Cr(VI) were 78%, 95% and 100% within 100 minutes, respectively.

Embodiment 3

[0020] Embodiment 3: to the Cr (VI) solution that initial concentration is 40mg / L, add the nano-iron that prepares newly, as Figure 4 As shown, within 60 min, when the pH value was 4, the removal rate of Cr(VI) was 98%; when the pH value was 8, the removal rate of Cr(VI) dropped to 58%. That is, the reduction rate of Cr(VI) by zero-valent iron decreases with the increase of pH value.

[0021] The equation for the reaction is:

[0022] Cr 2 o 7 2- +2Fe -0 +14H + →2Cr 3+ +2Fe 3+ +7H 2 o

[0023] wxya 3+ +(1-x)Fe 3+ +3H 2 O→Cr x Fe 1-x (OH) 3 +3H +

[0024] wxya 3+ +(1-x)Fe 3+ +2H 2 O→Cr x Fe 1-x (OOH)+3H + .

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Abstract

The invention discloses a method for removing chromium (VI) in water by stabilized nanoscale iron in air. The activity of the nanoscale iron stored in the air for two months is not influenced, and the removal effect of the nanoscale iron is much better than common iron powder. 0.4-0.6 g / L nanoscale iron is added into the solution of 40 mg / L Cr (VI), so as to have reduction reaction under normal temperature and normal pressure, and the Cr (VI) removal rate can be over 78 percent within 100 minutes. Under the condition that the pH value is lower, the removal effect is better. Compared with the common iron powder, the nanoscale iron has the advantages that the particle diameter is small; the specific surface area is large; the activity is much higher in the reaction with the Cr (VI); and the reaction time is greatly shortened. The product is widely applicable to the fields of environmental pollution treatment and environment remediation and has better market prospect.

Description

technical field [0001] The invention relates to the application field of nanotechnology, in particular to a method for removing hexavalent chromium pollution in water by air-stabilized nano-iron. Background technique [0002] Chromium and its compounds are essential raw materials for metallurgical industry, metal processing, electroplating, tanning, paint, pigment, printing and dyeing, pharmaceutical, photographic plate making and other industries. Due to the inability to effectively control and unreasonably discharge the chromium-containing wastewater produced by these industries, there is often serious chromium pollution in surface water and groundwater in many areas. Chromium mainly exists in two forms of Cr(III) and Cr(VI) in water. Cr(VI) has high solubility and mobility, and has carcinogenic, teratogenic and mutagenic effects. Therefore, the remediation technology of Cr(VI) pollution has attracted widespread attention. In recent years, researchers at home and abroad ...

Claims

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Application Information

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IPC IPC(8): C02F1/62C02F1/70C02F101/22
Inventor金朝晖李铁龙耿兵
OwnerNANKAI UNIV